title: Aminoglycoside resistance genes sgm and kgmB protect bacterial but not yeast small ribosomal subunits in vitro despite high conservation of the rRNA A-site.
abstract: The aminoglycoside resistance genes sgm from Micromonospora zionensis and kgmB from Streptomyces tenebrarius were cloned into a yeast expression vector to test whether the encoded prokaryotic methylases can modify the 18S rRNA A-site and thus confer resistance to G-418. Despite the detectable presence of mRNAs in yeast cells, neither G-418-resistant yeast transformants nor positive western blot signals were obtained. Neither methylase was capable of methylating 40S subunits despite very high conservation of the antibiotic rRNA binding sites. However, the results provide novel insight into the action of Sgm by showing that it methylates the same site as KgmB, i.e. G1405 in 16S rRNA.
authors.affiliation: Institute of Molecular Genetics and Genetic Engineering, Vojvode Stepe 444a, P.O. Box 23, 11010 Beograd, Serbia. tatjanai@eunet.yu
authors.forename: Tatjana Ilic
authors.initials: TI
authors.lastname: Tomic
authors.forename: Ivana
authors.initials: I
authors.lastname: Moric
authors.forename: Graeme L
authors.initials: GL
authors.lastname: Conn
authors.forename: Branka
authors.initials: B
authors.lastname: Vasiljevic
mesh_terms: D000617:Aminoglycosides / Q000494:pharmacology*; D001665:Binding Sites; D003001:Cloning, Molecular; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D005839:Gentamicins / Q000494:pharmacology*; D008780:Methyltransferases / Q000235:genetics / Q000378:metabolism*; D012329:RNA, Bacterial / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012337:RNA, Ribosomal, 18S / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012270:Ribosomes / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000201:enzymology / Q000235:genetics
chemical_list: D000617:Aminoglycosides; D005839:Gentamicins; D012329:RNA, Bacterial; D012333:RNA, Messenger; D012336:RNA, Ribosomal, 16S; D012337:RNA, Ribosomal, 18S; C010680:antibiotic G 418; D008780:Methyltransferases; C035181:rRNA (adenosine-O-2'-)methyltransferase